Germanium and arsenic are both group 14 elements, but they have quite different properties. Germanium is a metalloid, while arsenic is a nonmetal. Germanium is a shiny, silver-white solid, while arsenic is a brittle, gray solid. Germanium is a semiconductor, while arsenic is a poor conductor of electricity. Germanium is used in transistors and other semiconductor devices, while arsenic is used in pesticides and herbicides.

The main reason why germanium and arsenic are not more similar is that they have different electronic configurations. Germanium has four valence electrons, while arsenic has five. This difference in electronic configuration leads to different chemical properties. For example, germanium is more likely to form covalent bonds, while arsenic is more likely to form ionic bonds.

In addition, germanium and arsenic have different atomic radii. Germanium has an atomic radius of 122 picometers, while arsenic has an atomic radius of 115 picometers. This difference in atomic radii leads to different physical properties. For example, germanium is denser than arsenic.

Therefore, while germanium and arsenic are both group 14 elements, they have quite different properties due to their different electronic configurations and atomic radii.